[e2e] TCP Performance with Traffic Policing

[Agarwal, Anil]

Barry,

Can you also post the details of the policer settings used
for these tests?

Is ctcp enabled for Windows 7?

Anil

-----Original Message-----
From: end2end-interest-bounces at postel.org
[mailto:end2end-interest-bounces at postel.org] On Behalf Of Barry
Constantine
Sent: Tuesday, August 16, 2011 4:37 PM
To: anil at cmmacs.ernet.in
Cc: end2end-interest at postel.org
Subject: Re: [e2e] TCP Performance with Traffic Policing

Hi Anil,

Attached is a Word document with the sequence charts from Wireshark.

The 64KB and 128KB window sizes are shown for each OS.

Thanks,
Barry

-----Original Message-----
From: anil at cmmacs.ernet.in [mailto:anil at cmmacs.ernet.in] 
Sent: Saturday, August 13, 2011 4:24 PM
To: Barry Constantine
Cc: anil at cmmacs.ernet.in; end2end-interest at postel.org
Subject: RE: [e2e] TCP Performance with Traffic Policing

Hi Barry:

Would be glad to see the plots/sequence data in case you would like to
share them.

If the cause is burst, then the next interesting question whould be: why
the same TCP sender reacted quite differetnly to different (standard)
clients when the policing was in between and normal otherwise.

Anil

> Hi Anil,
>
> Your assessments seem reasonable and I will look at the packet
captures
> with Wireshark as you suggest.
>
> Also, thanks for pointing me to the old post; it was useful as well.
>
> -Barry
>
> -----Original Message-----
> From: anil at cmmacs.ernet.in [mailto:anil at cmmacs.ernet.in]
> Sent: Saturday, August 13, 2011 3:15 PM
> To: Barry Constantine
> Cc: end2end-interest at postel.org
> Subject: Re: [e2e] TCP Performance with Traffic Policing
>
> Hi Barry,
>
> Quite  interesting
>
> I would guess that the different flows (Linux, XP and Win7) in your
> experiment might have expressed varying bursty patterns, and that
would
> have made the policing process to treat these flows differently. A
time vs
> sequence plot on either side of the policing box should help to bring
out
> the real dynamics.
>
> Also, there was a similar post in e2e almost about a decade ago.
> http://www.postel.org/pipermail/end2end-interest/2002-June/002154.html
>
> It is worth having a look
>
> Anil
>
>> Hi,
>>
>> I did some testing to compare various TCP stack behaviors in the
midst
>> of
>> traffic policing.
>>
>> It is common practice for a network provider to police traffic to a
>> subscriber level agreement (SLA).
>>
>> In the iperf testing I conducted, the following set-up was used:
>>
>> Client -> Delay (50ms RTT) -> Cisco (with 10M Policing) -> Server
>>
>> The delay was induced using hardware base commercial gear.
>>
>> 50 msec RTT and bottleneck bandwidth = 10 Mbps, so BDP was 62,000
bytes.
>>
>> Ran Linux, Windows XP, and Windows 7 clients at 32k, 64k, 128k window
>> (knowing that policing would
>> kick in at 64K)
>>
>>                Throughput for Window (Mbps)
>>
>> Platform              32K        64K        128K
>> --------------------------------------------
>> Linux                     4.9         7.5         3.8
>> XP                          5.8         6.6         5.2
>> Win7                     5.3         3.4         0.44
>>
>>
>> Do anyone have experience with the intricacies of the various OSes in
>> the
>> midst of
>> Traffic policing?  I was surprised to see such a variation in
>> performance,
>> especially since Windows 7 is supposed to more advanced than XP,
>>
>> I am going to comb through the packet captures, but wondered if
anyone
>> had
>> insight.
>>
>> Thank you,
>> Barry
>>
>>
>>
>
>